Load-brake.



E. H. DEWSON.

LOAD BRAKE.

APPLICATION FILED MAY 2a, 1913.

1,089,401 Patented Mar. 10, 191

V Y Q V NESSES INVENTOR UNITED STATldl S; OFFICE.

EDWARD I-I. DEWSON, OF NEW YGRK, N. Y., ASSIGNQR TO THE WESTINGHOUSE AIRBRAKE COMPANY, OF WILIVIERDING, PENNSYLVANIA, A CORPORATION OF PENN-SYLVANIA.

To all whom it may concern Be it known that I, EDWARD H. Dnwson, acitizen of the United States, residing at New York, in the county of NewYork and State of New York, have invented new and useful Improvements inLoad-Brakes, of which the following is a specification.

This invention relates to fluid pressure brakes, and more particularlyto a brake equipment adapted to provide a higher degree of braking powerwhen the car is loaded than when the car is light.

The principal object of my invention is to provide electricallycontrolled means governed according to the load on the car forregulating the braking power.

In the accompanying drawing; Figure 1 is a diagrammatic View of a carair brake equipment showing my improvement applied thereto; and Fig. 2an elevational view, partly in section, of the electrically controlledload brake device in the light braking position.

My invention is more particularly designed for traction service and isillustrated as applied in connection with a straight air brake equipmentsuitable for single car operation.

As shown in Fig. 1 of the drawing, the car equipment may comprisestraight air brake valves 1 and 2 located at opposite ends of the carand adapted to supply fluid under pressure to and release the same froma straight air pipe 3. According to my invention, two brake cylinders 4:and 5 are employed, the brake cylinder 1 being the light brake cylinderand having a pipe 6 connecting the same directly to the straight airpipe 3. The brake cylinder 5 is an additional brake cylinder which isadapted to be automatically cut in with the brake cylinder 4t when thecar is loaded.

An electrically controlled device 7 is provided for controllingcommunication to the load brake cylinder 5 and preferably comprises aslide valve 8 contained in valve chamber 9 and electro-magnets 10 and 11for operating said valve. A pipe 12 leading from the straight air pipe 3is in constant communication through a port 13 in the seat of slidevalve Swith valve chamber 9 and a port 14 controlled by said valvecommunicates with pipe 15 leading to the load brake cylinder 5.

Specification of Letters Patent. Patented D13 10, 1914 Application filedMay 28, 1913.

Serial No. 770,295.

The respective electric circuits of the electro-magnets 10 and 11 arepreferably controlled by a switch device, the operation of which isgoverned according to the load on the car. For this purpose I provide aswitch arm 16 pivotally mounted on a casting 17 secured to the springplank 18 of the truck and having at one end a contact 19 adapted in oneposition to engage a stationary contact 20 connected to circuit wire 21of magnet 10 and in another position to engage contact 22 connected tocircuit wire 23 of magnet 11. The circuit wire 21 includes a source ofcurrent 2 1 and wire 23 has a source of current 25 and when the switcharm makes contact with one of the stationary contacts, the correspondingmagnet is energized by completing the ground connection.

The switch arm is operated by the movement of the car body and as shownthe end of the switch arm opposite to the contact end is inserted in anopening of a depending member 26 which may be connected to move with thecar bolster, a certain amount of lost motion being permitted in saidopening, so that ordinary slight movements of the car body on itssprings will be ineffective to operate the switch arm.

A quick make and break device may be applied to the switch arm, such asa spring pressed member 27 pivotally connected to the contact end ing tothrow the switch arm in one direction or the other as the same crossesthe neutral axis of the spring device.

When the car is loaded, the car springs are compressed and the switchlever 16 is moved to the load position, as shown in Fig. 1 of thedrawing, in which the circuit of magnet 10 is closed through contact 20.The energization of magnet 10 thereupon moves the valve 8 to theposition uncovering port 14:, so that when the brakes are applied bysupplying fluid to the straight air pipe 3 through the usual operationof the straight air brake valve, fluid is also supplied from the valvechamber 9 through port 1 1 and pipe 15 to the load brake cylinder 5 aswell as directly to the brake cylinder 1 through pipe 6. "When the caris light, the switch arm 16 is thrown to its other position by theupward movement of the car body on its springs and the circuit of magnet11 is closed through contact 22 and circuit wire of the switch arm andtend- 23, while the circuit of magnet 10 is opened. The energization ofmagnet 11 causes the movement of the slide valve 8 to the position shownin Fig. 2, in which a cavity 28 therein connects the port 14 with anatmospheric exhaust port 29. The load brake cylinder is thus open to theatmosphere when the car is light and when applications of the brakes aremade, fluid is only supplied through the straight air pipe to the lightbrake cylinder 4:.

It will now be evident that I have provided a simple and compactconstruction whereby the braking power is automatically increased inmaking applications of the brakes when the car is loaded, and withoutany attention on the part of the operator.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. The combination with a fluid pressure operated brake apparatusadapted to be adjusted to give light braking power on light cars andheavy braking power on loaded cars, of electrically controlled meansgoverned by the load on the car for controlling the adjustment of saidbrake apparatus.

2. In a fluid pressure brake, the combination with a brake cylinder forproviding braking power on a light car and a brake cylinder adapted tobe cut in to provide increased braking power on a loaded car, ofelectrically controlled means governed by the load on the car forcutting in said load brake 1 cylinder.

3. The combination with a fluid pressure operated brake apparatusadapted to be adjusted to give light braking power on light cars andheavy braking power on loaded cars, of electrically operated means forcontrolling the adjustment of said brake apparatus and an electricswitch operated according to the load on the car for control- I ling thecircuit of said electrically controlled means.

l. In a fluid pressure brake, the combina- 'tion with a brake cylinderfor providing braking power on light cars and a brake cylinder forproviding increased braking power on loaded cars, of a valve forconnecting up said load brake cylinder to receive fluid under pressurein applying the brakes and an electro-magnet having the electric circuitthereof controlled according to the load on the car for operating saidvalve.

5. In a fluid pressure brake, the combination with a brake cylinder forproviding braking power on light cars and a brake cylinder for providingincreased braking power on loaded cars of a valve for connecting up saidload brake cylinder to receive fluid under pressure in applying thebrakes, an electro-magnet for operating said valve to connect up saidload brake cylinder, an electro-magnet for operating said valve to cutout said load brake cylinder, and a switch operated by the movement ofthe car according to the load thereon for controlling the electriccircuits of said magnets.

6. The combination with a straight air brake comprising a brake cylinderand a brake valve for supplying fluid under pressure to the brakecylinder to effect an application of the brakes, of a second brakecylinder and an electrically controlled valve governed according to theload on the car for connecting up said second brake cylinder to receivefluid under pressure upon operation of the brake valve.

In testimony whereof I have hereunto set my hand.

, EDWARD H. DEYVSON. Witnesses ALEXAND R BEGG, E. W. DAVIS.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Iatent- Washington. I). G.

